One of San Francisco’s most iconic buildings, the Frank Lloyd Wright designed storefront at 140 Maiden Lane, has a brand new tenant. Neapolitan menswear brand, Isaia—which specializes in custom tailoring and luxe separates—opens its doors today to the public. Isaia (it’s pronounced is-I-E-ah) worked hand and hand with the famed architect’s preservation team to ensure that Lloyd Wright’s landmark building remained untouched. The mousetrap like entrance continues to exist as do the spiraling walkway that leads to a second floor and the wooden cabinetry that is built into the walls.

Isaia’s team did breath new life into the space with a fresh coat of paint, new sage grey carpeting, and lots of indulgent accents. The resulting boutique is modern yet traditional, spacious yet cozy, historic yet contemporary. “This year marks our 60th year as a brand. It is personally very important to me that we are always pushing to do new things, while paying homage to our heritage. Opening a shop in the landmarked Frank Lloyd Wright building, accomplishes just that,” Gianluca Isaia, the third generation CEO of the clothing line told Haute Living.

The new Isaia has red velvet banquettes, a pea green round couch, vintage-inspired rugs, Flora Grubb succulents, and fish-print bathroom wallpaper. The space feels sort of like a private mens club. There are two incredible antique bars, unique and indigenous to the Bay of Naples. Downstairs is a hidden cabinet bar that opens with a secret key. Upstairs is a larger bar, a vintage Campari artifact, that is fantastic. There is an area devoted to music with an-old school record player and moderate collection of records. A red lacquered piano sits in front of an assortment of cellphones that look oddly like relics even though they are only 10 years old. Unique head frescos illustrate the brand’s Italian heritage.

Then, of course, are the clothes. 90 percent of Isaia’s collection is handmade and it shows in the tailoring. Jackets are crafted in the same technique that Chanel uses. Coats are lightweight and stylish with meltons that change with the season. Cashmere sweaters, denim, ties, shirts, even accessories like cellphone and laptop cases can be found at the men’s boutique. Isaia specializes in custom suites and upstairs is an area designated specifically for this purpose. Fashionable men select from an extensive collection of fabrics, choosing everything from the lining inside the jacket to the buttons on the pants—thus, being able to make the ultimate personalized suit.

Although the brand has been around since 1957, it waited until finding the perfect location to open a store in San Francisco. They had their eye on the Lloyd Wright building for years before it finally became a reality. “We wanted to bring the full Isaia experience to our San Francisco customers, who have been asking us to open a store here for years,” Gianluca said. “We are very lucky to have found the perfect space in this iconic FLW building. And also. . . I like the trolleys here.” He adds, “experience is a big part of what we offer to our customers. We want each of our stores to have a setting where our guests can relax and escape, while at the same time, enjoying anticipatory service for whatever their needs are.” The shop has a speedy Gonzalez service where a suit can be ready to go in seven to 14 days. Below the building is a dedicated tailor’s shop with craftpeople who trained in Naples.

In honor of the new store’s opening, Isaia hosted a lively party last night. The part of Maiden Lane that is directly adjacent to the building was closed off to the public and covered with a festive red carpet. There was caviar and Aperol spritzes, plus a fun photo opportunity on a shiny red Vespa. Gianluca held court—mingling and greeting guests that included Katie and Todd Traina, Scott and Nina Stanford, and Michael and Sara Franti. Adam Cahan escorted his wife, model Anne V, who looked stunning in an Isaia suit that had been tailored to fit a female’s body. Other notables who enjoyed the party? Roman Coppola, Sonya Molodetskaya and Willie Brown, and Alexandra and Spencer Wells.